This key antioxidant mops up free radicals generated in the liver during detoxification. Vitamin C supplementation can also reduce risk for gallstones, according to a recent study, and protects lung cells from air-pollution damage. Dose: Start with 1,000 mg daily and increase by 500-mg increments to 2,000 mg or more, especially if you often run, walk, or cycle near traffic, says Crinnion. Reduce dose if loose stools result.